Biosurfactants (eBook)

Preface 6
Contents 8
Biosurfactants: A General Overview 10
1 Introduction 11
2 Physicochemical Properties, Formation of Micelles, and Other Aggregates 11
3 Biosurfactant Production in the Environment 15
4 Conclusions 16
References 17
Rhamnolipids: Detection, Analysis, Biosynthesis, Genetic Regulation, and Bioengineering of Production 21
1 Introduction and Overview 22
2 Rhamnolipid Structure, Detection, and Analysis 24
2.1 Structure 24
2.2 Methods of Detection and Analysis 25
2.2.1 Qualitative Methods 25
2.2.2 Quantitative Methods 26
3 Biosynthesis and Genetic Regulation 29
3.1 Biosynthesis of Rhamnolipids 30
3.1.1 Biosynthesis of the Lipid Moiety of Rhamnolipids 30
3.1.2 Biosynthesis of Rhamnolipids-Rhamnose Moiety 35
3.1.3 Three Last Enzymatic Reactions in Rhamnolipids Biosynthesis 36
3.2 Regulation of Rhamnolipid Biosynthesis 37
3.2.1 Genetic Regulation of Rhamnosyltransferases 38
3.2.2 Genetic Regulation of Biosynthesis of Sugar Moiety 40
3.2.3 Regulation of Rhamnolipid Production by Environmental Factors - Links Between Quorum Sensing and the Environment 41
4 Bioengineering of Rhamnolipid Production 42
4.1 Production by P. aeruginosa 42
4.1.1 Fermentation Strategies 42
4.1.2 Foaming Problems Encountered During Fermentative Production 45
4.1.3 Nutritional Factors Affecting Rhamnolipid Production 46
4.1.4 Recovery of Rhamnolipids 48
4.2 Alternatives to P. aeruginosa for Rhamnolipid Production 49
4.2.1 Heterologous Production of Rhamnolipids 49
4.2.2 Non-P. aeruginosa Rhamnolipid Producers 50
5 Conclusion: Prospectives for the Industrial Production of Rhamnolipids 51
References 51
Surfactin and Other Lipopeptides from Bacillus spp. 64
1 Introduction: History of Lipopeptide Discovery in Bacillus spp. 65
1.1 Surfactins from Asia 65
1.2 Iturins from Africa 66
1.3 Concomitant Discovery of Fengycin and Plipastatin 67
1.4 Kurstakins, a New Family of Lipopeptides from Bacillus spp. 67
1.5 Conclusion 67
2 A High Diversity of Structures 67
2.1 Surfactin and Related Compounds 68
2.2 The Family of Iturins 70
2.3 Fengycin or Plipastatin, Who´s Who? 71
2.4 Other Lipopeptide Compounds, the Kurstakins 71
2.5 Conclusion 72
3 Catalytic Assembly Lines for the Biosynthesis of Lipopeptides: From the Genes to the Biomolecules 72
3.1 Modular Enzymes: A Complex Catalytic Machinery Dedicated to the Biosynthesis of Secondary Metabolites 72
3.1.1 Discovery of the Non-ribosomal Peptide Synthesis 72
3.1.2 The Main Catalytic Domains 74
3.1.3 Secondary Catalytic Domains 74
3.1.4 Protein-Protein Interactions 75
3.2 Non-ribosomal Peptide Synthesis of Surfactin and Lichenysin 75
3.2.1 The Surfactin Operon 75
3.2.2 The Lichenysin Operon 76
3.2.3 Structure of an Entire Termination Module 76
3.3 The Hybrid PKS/NRPS Complex Involved in Iturin Biosynthesis 77
3.4 Non-ribosomal Peptide Synthesis of Fengycin and Plipastatin 78
3.5 The Recent Discovery of the Biosynthesis Mechanism of Kurstakin 78
3.6 Conclusion 79
4 A Complex Regulation of the Biosynthesis 79
4.1 Quorum Sensing and Surfactin Efflux 79
4.2 Influence of Environmental Factors 81
4.3 Conclusion 82
5 Physico-chemical Properties and Biological Activities: A Strong Relationship 82
5.1 Surfactin: A Potent Biosurfactant, Which Combines High Effect on Surface Tension and Low Critical Micellar Concentration 82
5.2 Iturin: A Strong Antifungal Compound 84
5.3 Fengycin and Plipastatin: Immunomodulators in Plants and Animals 84
5.4 Lipopeptides: Versatile Weapons for Biocontrol of Plant Diseases 85
5.5 Conclusion 85
6 New Strategies for an Optimal Production of Novel or Existing Lipopeptidic Compounds 85
6.1 Surfactin Synthetases Re-engineering 86
6.2 Combinatorial Synthesis of Lipopeptides 86
6.3 Directed Biosynthesis and Molecular Optimisation 87
6.4 New Bioprocesses for Continuous Production and Extraction of Lipopeptides 87
6.4.1 Quantitative Evaluation of Surfactin Concentrations 87
6.4.2 Purification of Surfactin 88
6.4.3 Bioprocesses for Lipopeptide Production 88
6.5 Conclusion 89
7 Industrial Applications: Dream and Reality 89
7.1 Main Applications 89
7.2 Conclusion 90
References 90
Serrawettins and Other Surfactants Produced by Serratia 99
1 Introduction 100
2 Detection and Analysis of Serratia Biosurfactants 100
2.1 S. marcescens Wetting Activity and the Ways to Identify It 101
2.1.1 Analysis of Serratia Lipids by Thin-Layer Chromatography 102
2.1.2 Surface Activities of Isolated Serrawettins 104
2.2 Other Serratia Wetting Agents 105
3 Production Characteristics 105
3.1 Association of the Production of Serratia Surfactants with Extracellular Vesicles 105
3.2 Budding of Vesicles Filled with Serratia Surfactants 106
4 Chemical Structure of Serrawettins and Rubiwettins 107
4.1 Serrawettin W1, W2, and W3 107
4.2 Rubiwettin R1 and RG1 109
5 Physiological Functions of Biosurfactants 110
5.1 Flagellum-Independent Bacterial Spreading Growth 110
5.2 Flagellum-Dependent Bacterial Spreading Growth 113
5.3 Other Biological Activities of Serrawettins 115
6 Genetics of Biosynthesis and Regulation 116
6.1 Genes Involved in Serrawettin W1 Biosynthesis 116
6.2 Quorum-Sensing Regulation of Serrawettin Biosynthesis 119
6.3 Global Regulator Genes Concerned with Exolipid Production 120
7 Concluding Remarks 122
References 123
Trehalolipids 127
1 Introduction 128
2 Trehalolipid-Producing Bacteria 128
3 Chemical Structures 132
3.1 Cord Factor: A Trehalose Diester from Mycobacteria 133
3.2 Trehalose Lipids from Rhodococcus 135
3.2.1 Trehalose Diesters 135
3.2.2 Trehalose Tetraesters Produced by Rhodococcus and Related Bacteria 139
3.2.3 Octaacyltrehalose from Rhodococcus sp. H13-A 140
4 Physicochemical Property 141
5 Biological Activity 141
5.1 Trehalose Lipids in Mycobacteria 142
5.2 Trehalose Lipids from Rhodococcus 142
6 Biosynthesis 143
7 Production 143
7.1 Substrates Used for Trehaloselipids Production 144
7.2 Cell Wall Association 145
7.3 Growth-Associated Production 145
References 146
Mannosylerythritol Lipids: Microbial Production and Their Applications 150
1 Introduction 151
2 Microbial Sources and Structural Diversity of MEL 152
2.1 MEL-A Producers 156
2.2 MEL-B Producers 156
2.3 MEL-C Producers 157
2.4 Effect of Addition of Different Sugars on the Type of MEL Produced 159
3 Significance of MEL 159
4 Genetic Regulation and Biosynthesis of MEL 160
5 Evolutionary Relationship Among MEL Producers 164
6 Bioprocesses Used for MEL Production 165
6.1 Factors Affecting MEL Production 167
6.1.1 Carbon Source 167
6.1.2 Nitrogen Source 167
6.1.3 Effects of Hydrophilic Precursor 167
6.1.4 Effect of Temperature 168
6.1.5 Time Course of MEL Production 168
7 Phase Behavior of MEL 168
7.1 Formation of Thermodynamically Stable Vesicles and Coacervates by MEL 169
7.2 Multilamellar Vesicles and Large Unilamellar Vesicles 170
7.3 Lyotropic-Liquid-Crystalline Phases of MEL 171
7.4 Self-Assembled Monolayer Structures of MEL 172
8 Applications 174
8.1 Antimicrobial Activity of MEL 174
8.2 MEL Induces Cell Differentiation and Apoptosis 175
8.3 Purification of Glycoproteins 175
8.4 Vehicles for Gene Delivery 175
8.5 Inhibition of Ice Agglomeration 176
8.6 Cosmetic Applications of MEL 176
9 Perspectives 176
10 Conclusions 177
References 178
Sophorolipids 183
1 Introduction: A Brief History 184
2 Structure and Properties 185
3 Producing Microorganisms 187
3.1 Rhodotorula bogoriensis 187
3.2 Candida apicola 188
3.3 Candida bombicola 188
3.4 Wickerhamiella domercqiae 189
3.5 Candida batistae 189
4 Biosynthesis 189
4.1 Feedstock 189
4.2 Sophorolipid-Specific Enzymes 197
4.2.1 Hydroxylation of the Fatty Acid and Its Consequences 197
4.2.2 Coupling the Glucose Molecules 199
4.2.3 Final Modifications 200
5 The Fermentation Process 200
5.1 Culture Conditions 200
5.2 Substrates 201
5.3 Downstream Processing 201
6 Genetic Engineering of C. bombicola 201
6.1 Developing the Molecular Tool Box 202
6.2 Genetic Engineering of C. bombicola for the Production of Medium-Chain Sophorolipids 203
7 Applications of Native Sophorolipids 203
8 Modified Sophorolipids and Their Applications 206
9 Conclusion 208
References 209
Index 215